A lathe is a machine tool that spins a workpiece to shape it by applying tools to the workpiece to perform operations that are typically symmetric around an axis of rotation. Lathes are used in woodworking, metalworking, and other areas. The typical lathe has a bed, which is preferably one or more horizontal beams along which certain lathe parts move. A lathe may have a stand which sits on the floor and raises the lathe bed to a suitable height for working.
In the traditional lathe design, a headstock is provided at one end of the bed (almost always the left side when facing the front of the lathe). A spindle which rotates on bearings in the headstock is on a horizontal axis parallel to the bed. The headstock powers the spindles to provide rotating motion to the workpiece, which is gripped by a chuck along the exterior of the headstock. In the typical modern lathes, the power source for the rotating spindle is an electric motor, attached to the headstock in some way. In addition to the spindle, the headstock often contains parts to adjust the motor speed to provide various spindle rotating speeds. This may be a gear train or some type of pulley arrangement. Sometimes the motor has electronic speed controls that can perform this function without a complex gearing arrangement.
At the other end of the bed from the headstock, the typical lathe has a tailstock, which can be repositioned by sliding it along the bed and locking it in place with a locking nut. The tailstock contains a barrel usually used for gripping of various types of tooling, or holding a center for supporting thin shafts while they are being turned on the lathe.
Between the headstock and tailstock, metalworking lathes have a carriage (comprising a saddle and apron). The carriage is topped with a cross-slide, which is a flat piece that sits crosswise on the bed. A leadscrew moves the cross-slide along the bed. For example, sitting atop the cross-slide is usually another slide called a compound rest, which provides 2 additional axes of motion, rotary and linear. Atop the compound rest there is typically a toolpost, which holds a cutting tool for removing material from the workpiece upon which the lathe is operating. In a typical shop lathe system or typical metalworking lathe, the headstock is fixed in place relative to the lathe bed, and the carriage and tailstock move relative to the headstock to perform lathe operations. In a metalworking lathe, a hardened cutting tool is mounted to the toolpost and moved against the workpiece to remove metal from the workpiece. The toolpost is operated by leadscrews that can reposition the tool along multiple dimensions.
The construction of a typical metalworking lathe fixes the headstock in place at the left end of the bed, and allows movement of the carriage and tailstock along the bed. The lathe is typically manufactured with the bed joined to the headstock in a manner that does not allow replacement or reconfiguration by the lathe operator.
In operation, a metalworking lathe produces metal shavings and cuttings or other waste pieces that may get caught on the bed and cause damage to the sliding surface of the bed. Also, the bed may be damaged or dented by impacts from heavy pieces of metal being worked on in the lathe. A damaged bed requires expensive resurfacing that often entails excessive downtime in the lathe operating schedule. Further, in operation, a typical lathe requires removing the workpiece from the lathe to perform additional milling or drilling operations that do not have the same symmetrical axis as the operations being performed on the lathe. Precision alignment and speed of operations often suffer with such repositioning of the workpiece, which may occur multiple times during the metalworking process.